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Molten carbonate fuel cells (MCFCs) offer several advantages that are attracting an increasingly intense research and development effort. Recent advances include improved materials and fabrication techniques as well as new designs, flow configurations, and applications. Several factors are holding back large-scale implementation of fuel cells, though, especially in distributed energy generation, a major one being their long response time to changing parameters. Alternative mathematical models of the molten carbonate fuel cell stack have been developed over the last decade. This study investigates a generic molten carbonate fuel cell stack with a nominal power output of 1 kWel. As daily, weekly, and monthly variations in the electrical power load are expected, there is a need to develop numerical tools to predict the unit’s performance with high accuracy. Hence, a fully physical dynamic model of an MCFC stack was developed and implemented in aspen hysys 10 modeling software to enable a predictive analysis of the dynamic response. The presented model exhibits high accuracy and accounts for thermal and electrochemical processes and parameters. The authors present a numerical analysis of an MCFC stack in emergency scenarios. Further functionality of the model, which was validated using real operational data, is discussed.

The use of waste heat in many branches of industry is limited due to temperature in the range of 30–100 °C. One of the methods of using waste heat are devices that implement the Organic Rankine Cycle (ORC). In currently used ORC systems, the heat source temperature is at least 80 °C, while the low temperature heat source (usually atmospheric air) has a temperature of 30 °C. The work analyzes the influence of the organic fluids properties on the performance of the novel, proposed installation with electric power output 1 kW driven by the waste heat and working based on the ORC. In comparison to a commonly used ORC installation the examined installation is characterized by one essential difference: expansion process. The expansion device used in a typical ORC structure, is replaced by two connected tanks filled by secondary fluid, between which the hydraulic turbine is installed. The basic operation parameters in nominal conditions were determined for ten selected refrigerants: R134a, R152a, R227ea, R236fa, R245fa, R290, R600a, R717, R1234yf, R1234ze(E). The boiling point 80 °C and the condensing temperature 30 °C were used as nominal conditions. Analogical calculations were also done for conventional ORC system working with the same parameters and providing the same electric power output. As a result of the analysis, it turned out that for the proposed device, the best refrigerant is ammonia, for which the 5.68% efficiency was obtained. Comparing the results with the achievements for a standard ORC system, it is almost twice lower (for ammonia ORC systems, the efficiency is 9.93). However, in the experimental installation it was decided to use R245fa refrigerant, because unlike ammonia it is not flammable and is not toxic. According to the analysis, the R245fa was one of the best refrigerants in terms of efficiency and, what is the most important, it did not mix with the glycerol used in the tanks as a secondary fluid. Theoretical analysis for fluid R245fa has shown that the total energy efficiency coefficient for whole proposed system will be at level 4.72%, while as a result of the experiment, it managed to achieve an efficiency level of 2.51%.

Molten Carbonate Fuel Cells (MCFCs) can be used as CO2 separators in fossil fuel power plants. Fossil fuel power plants emit flue gases with SO2 contaminants, thus the influence of SO2 on the operation of MCFC is investigated both theoretically and experimentally. The influence of SO2 contaminants (up 680 ppm) on MCFC performance was examined. The experimental investigation revealed there is a boundary limit where SO2 contamination could increase the MCFC voltage.

Development of the district heating system (DHS) is needed to achieve the Renewable Energy Directive goals. To maintain the economic profitability of DHN, the increase of intensity of heat production/consumption has to be ensured. Well, a known method is a cold production using an adsorption heat pump. However, developing a system suitable for implementation in the district heating companies is very difficult. As a solution, the authors propose a composite substation equipped with the adsorption heat pump and the heat/cold storage system based on a PCM.

This paper presents the model of heat exchanger dedicated to operate in supercritical CO2 cycles (Brayton). The models is built in the Ebsilon software and validated against literature available experimental data. Relatively compact design of the supercritical CO2 cycle elements required using radial turbomachinery and thin plate heat exchangers. Thus, it seems that there is no general relationships for the turbomachinery and real characteristics need to be used for constructing the models.

This paper presents the model of heat exchanger dedicated to operate in supercritical CO2 cycles (Brayton). The models is built in the EBSILON software and validated against literature available experimental data. Relatively compact design of the supercritical CO2 cycle elements required using radial turbomachinery and thin plate heat exchangers. Thus, it seems that there is no general relationships for the turbomachinery and real characteristics need to be used for constructing the models.

The paper presents an experimental investigation of using a Molten Carbonate Fuel Cell (MCFC) to reduce CO2 emission from the flue gas of a lignite fired boiler. The MCFC is placed in the flue gas stream and separates CO2 from the cathode side to the anode side. As a result, a mixture of CO2 and H2O is obtained from which pure CO2 can be obtained through condensation of water and carbon dioxide. The main advantages of this solution are: additional electricity generated, reduced CO2 emissions and higher system efficiency. The results obtained show that the use of an MCFC could reduce CO2 emissions by 90% with over 30% efficiency in additional power generation.

This article presents an analysis on possible ways of utilizing low-temperature waste heat. If well-designed, this could contribute to increasing the efficiency of power plants without introducing many complex changes to the whole system. The main analysis focuses on the location of the regenerative heat exchanger in the facility. This could differ with varying temperatures of working media in the system. The base for investigations was a 800 MW-class power unit operating in off-design conditions and supplied with steam from an BB2400 boiler. Modifications to the model were made using commercially available software and by applying the Stodola equation and the SCC method. It allowed to determine the most suitable position for installing the low-temperature heat exchanger. Calculations for off-design conditions show that, after making some modifications to the system, both heat and electricity generation could be increased through the addition of a low-temperature heat exchanger.

This work considers electronic conductance in a molten carbonate fuel cell and consequences of its existence. The voltage characteristics of cells show differences between a theoretical maximum circuit voltage and open circuit voltage (OCV). A relationship is assumed between the OCV value and electronic conductance. Based on experimental measurements an appropriate mathematical model was created. The model is used to calculate the temperature dependence of electronic conductance for the most popular types of electrolyte: Li2CO3/K2CO3. The results obtained point to the possible existence of a very close relationship between electronic conductance and open circuit voltage. This relationship enables OCV to be calculated when electronic conductance is known. Appropriate formulae can be determined. Temperature is one of the factors affecting electronic conductance. Other influencing factors do exist, but their impact on OCV is not well known. This article mentions some of them.

The paper presents an experimental investigation of using a Molten Carbonate Fuel Cell (MCFC) for reducing CO2 emission from the flue gas of a lignite boiler. The MCFC is placed in the flue gas stream and separates CO2 from the cathode side to the anode side. As a result, a mixture of CO2 and H2O is obtained; from which pure CO2 can be obtained by cryogenic condensation of water and carbon dioxide. The main advantages of this solution are: additional electricity generated, reduced CO2 emissions and higher system efficiency. The results obtained show that the use of an MCFC could reduce CO2 emissions by 90% with over 30% efficiency in additional power generation.

The paper presents an experimental investigation of using a Molten Carbonate Fuel Cell (MCFC) for reducing CO2 emission from the flue gas of a hard coal fired boiler. The MCFC is placed in the flue gas stream and separates CO2 from the cathode side to the anode side. As a result, a mixture of CO2 and H2O is obtained; from which pure CO2 can be obtained by water condensation. The main advantages of this solution are: additional electricity generated, reduced CO2 emissions and higher system efficiency. The results obtained show that the use of an MCFC could reduce CO2 emissions by 90% with over 35% efficiency in additional power generation.

This paper describes the model of the novel concept liquid piston engine, which is designed to convert low-grade waste heat into electricity. The proposed dynamic oriented model is implemented in Aspen Hysys that enables simulations dynamic simulation of various working agents. The simulation results were verified with experimental data obtained from the research installation. The proposed model demonstrated relatively small discrepancies with respect to experimental research, hence it could be used as a tool for research on optimization of an innovative power plant operation, i.e. various working agents, various operating pressures.